For several military applications and/or operational groups, weapons may need to be collapsible for ease of transportation to a field venue, and then easily assembled in the field. For example, rifles are frequently designed to be collapsible. One typical portion of a collapsible rifle assembly is the buttstock that forms the aft-most part of the assembled rifle, which is received and covers a recoil absorption appendage, or “receiver extension.” In general, modern conventional buttstocks are ergonomic since the buttstock forms the interface with the user's shoulder area, and adjustable along the receiver extension to further form fit the rifle to the user. One manner in which modern conventional buttstocks are made adjustable is via a slide lock mechanism, which provides a biasing pin that fits into a retaining feature, such as a pin seat or hole, provided along the receiver extension. A number of such pin seats or holes are so provided by the receiver extension to provide multiple adjustment points which are used to either lengthen or shorten the rifle as a user may desire.